Introduction # Distributed message brokers are the backbone of modern microservices architectures, enabling asynchronous communication, decoupling services, and providing a reliable way to handle data streams at scale.
Life Without a Rate Limiter # Imagine a public web API that allows clients to fetch user data without any rate limiting. Under normal conditions this might work, but during traffic spikes or abuse (e.g., bots or scrapers) the backend can be overwhelmed, leading to resource exhaustion, cascading failures, and poor availability for legitimate users. Without any form of control, a single noisy neighbor can starve others, increase infrastructure costs, and make it difficult to meet SLAs.
Every great architecture starts simple. But as we scale from a single monolith to a swarm of microservices, we hit a wall that only one pattern can break: the API Gateway. Phase 1: The Blissful Monolith # You have one server, one database, and one endpoint. Everything is easy:
